> Writing tests used to be a pain. This is no longer the case. It is ok to request unit tests/CI tests for each PR. These have never been more important since large refactors are becoming increasingly common. Human and LLM review may miss stuff but good tests should catch breakages.

The default behavior is not necessarily good. You end up with tests that match the code, but you don’t necessarily end up with tests that test the behavior you care about. And then, if the LLM tries to decide whether the code is correct, it can conclude “it matches the test so it must be right” regardless of whether it’s actually right.

TDD can help but is not a panacea.